Thermoplastic injection molded and flushable material

ABSTRACT

A water-dispersible injection-moldable composition includes partially-hydrolyzed polyvinyl alcohol (PVOH), polyethylene glycol (PEG), plasticizer, and a hydrophobic polymeric component, wherein the composition has a melt flow index of 5-180. The hydrophobic polymeric component can be a colorant within an ethylene matrix or polyethylene. The composition is flushable according to Guidance Document for Assessing the Flushability of Nonwoven Consumer Products (INDA and EDANA, 2006); Test FG 522.2 Tier 2—Slosh Box Disintegration Test. The PVOH has a hydrolysis of 87% to 89%.

BACKGROUND

The present disclosure relates generally to tampon applicators. Vaginaltampons are disposable absorbent articles sized and shaped (e.g.,cylindrical) for insertion into a women's vaginal canal for absorptionof body fluids generally discharged during the woman's menstrual period.Insertion of the tampon into the vaginal canal is commonly achievedusing a tampon applicator that comes initially assembled with thetampon.

Tampon applicators are typically of a two-piece construction, includinga barrel in which the tampon is initially housed and a plunger moveabletelescopically relative to the barrel to push the tampon out of thebarrel and into the vaginal canal. The barrel has a tip that generallyretains the tampon within the barrel until pushed through the tip by theplunger. In normal use, the applicator and more particularly the barrelof the applicator is held by the user by gripping one portion of thebarrel (e.g., toward the trailing or plunger end of the barrel) andinserting the barrel, tip end first, into the vaginal canal. The barrelis pushed partially into the canal so that a portion (e.g., toward theleading or exit end of the tampon barrel) is disposed within the vaginalcanal and is contact with the walls lining the canal. The plunger isthen used to push the tampon out through the tip of the barrel and intothe canal. The plunger and barrel are then removed from the vaginalcanal, leaving the tampon in place.

Flushable feminine care products provide consumers with discretion andconvenience benefits. Current plastic tampon applicators, however, aremade of injection molded materials such as polyolefins (e.g.,polypropylenes or polyethylenes) and polyesters that are notbiodegradable or renewable, as the use of biodegradable polymers in aninjection molded part is problematic due to their high cost and to thedifficulty involved with thermally processing such polymers. As aresult, consumers must dispose of tampon applicators in a separate wastereceptacle, which results in a challenge for consumers to dispose of theapplicators in a discrete and convenient manner. Furthermore, the soiledor used tampon applicator can also pose a biohazard or potential healthhazard. Although current plastic tampon applicators are not supposed tobe flushed, some consumers can nevertheless attempt to flush theapplicators in the toilet, which can lead to clogging of sewer pipes andmunicipal waste water treatment facilities. Attempts have been made tomold cold water-dispersible materials such as poly(vinyl alcohol) (PVOH)to alleviate these problems, but such attempts have not been successful.Instead, when using PVOH in tampon applicators, the materials must besolution processed so they can be formed into a tampon applicator thathas a thick enough wall, and such solution processing is a slow, costly,environmentally-unsustainable process that necessitates high energyrequirements. Further, although cardboard applicators have beendeveloped, the cardboard must often be coated to decrease thecoefficient of friction of the applicator to a comfortable level forconsumers, and the coatings used are not environmentally friendly andadd to the costs associated with forming the applicator.

Recent efforts on flushable applicators used a pin-dipping process andhydroxyl propyl methyl cellulose (HPMC) materials that were highlydispersible in cold water. The applicators, however, began dissolvingduring the insertion process and were extremely brittle and not amenableto current converting processes. Preliminary work produced a blend ofHPMC and a proprietary resin that is also dispersible in cold water andshown the capability to be injection molded. The large amount ofplasticizer used in these early formulations, however, proved to be anissue during long term storage.

As such, a need currently exists for a thermoplastic, water-dispersiblecomposition that can be injection molded, where such compositions can besuccessfully formed into a tampon applicator. A need also exists for awater-dispersible applicator that is comfortable to insert and that doesnot begin to break down upon insertion or during storage.

SUMMARY

In one aspect, a water-dispersible injection-moldable compositionincludes partially-hydrolyzed polyvinyl alcohol (PVOH), polyethyleneglycol (PEG), plasticizer, and a hydrophobic polymeric component,wherein the composition has a melt flow index of 5-180.

In an alternate aspect, a water-dispersible injection-moldablecomposition includes 55 wt. % to 75 wt. % partially-hydrolyzed polyvinylalcohol (PVOH), 15 wt. % to 25 wt. % polyethylene glycol (PEG), 9 wt. %to 14 wt. % plasticizer, and 3 wt. % to 4 wt. % hydrophobic polymericcomponent.

In another aspect, a water-dispersible injection-moldable compositionincludes 55 wt. % to 75 wt. % partially-hydrolyzed polyvinyl alcohol(PVOH), 15 wt. % to 25 wt. % polyethylene glycol (PEG), 9 wt. % to 14wt. % glycerin, and 0.5 wt. % to 4 wt. % polyethylene.

Objects and advantages of the disclosure are set forth below in thefollowing description, or can be learned through practice of thedisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be more fully understood, and furtherfeatures will become apparent, when reference is made to the followingdetailed description and the accompanying drawings. The drawings aremerely representative and are not intended to limit the scope of theclaims.

FIG. 1 is a perspective view of one aspect of a water-dispersible tamponapplicator as contemplated by the present disclosure;

FIG. 2 is a schematic view of a representative injection moldingapparatus used to manufacture the tampon applicator of FIG. 1; and

FIG. 3 is a schematic plan view of a standard test sample mold used inthe present application.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present disclosure. The drawings are representationaland are not necessarily drawn to scale. Certain proportions thereofmight be exaggerated, while others might be minimized.

DETAILED DESCRIPTION

Generally speaking, the present disclosure is directed to athermoplastic composition that is water-sensitive (e.g., water-soluble,water-dispersible, etc.) in that it loses its integrity over time in thepresence of water, yet also has a high enough melt flow index and a lowenough melt viscosity such that it can be molded into an article such asa tampon applicator. For instance, the thermoplastic compositiondescribed herein has a high enough melt flow index and a low enough meltviscosity such that it can be injected molded. The composition containspartially-hydrolyzed PVOH, polyethylene glycol (PEG), a plasticizer, anda hydrophobic polymeric component such as polyethylene. The desiredwater-sensitive attributes and mechanical properties of the compositionand the resulting molded articles, such as tampon applicators, can beachieved in the present disclosure by selectively controlling a varietyof aspects of the composition, including the nature of each of thecomponents employed, the relative amount of each component, the ratio ofthe weight percentage of one component to the weight percentage ofanother component, and the manner in which the composition is formed.

The central aspect of the disclosure is that a tampon applicator barrelis sufficiently water dispersible (passes slosh box test), yet itsproperties are not significantly deteriorated before and during tamponinsertion (passes insertion force test). If a tampon applicator beginsto disperse too much during insertion, the barrel begins to stick andthe insertion force increases too much. The present disclosure preventsthis by delaying or significantly slowing water dispersion during tamponapplicator insertion. This delay is linked to the surface morphology ofthe barrel and the presence of a hydrophobic polymer such aspolyethylene (PE) at the surface.

This surface is created by fast cooling of the barrel in the mold of auniform anhydrous ternary thermoplastic blend of PVOH, PEG, and smallamount of PE to a temperature below the Upper Critical SolutionTemperature (UCST) of the blend. During molding, when the temperaturefalls below the blend UCST, the PE migrates to the surface with the PEG.During this migration the PE migrates initially earlier and faster thanthe PEG to the surface, but later the PEG begins to displace the PE atthe surface. The PEG does not begin to migrate until the blendtemperature is below the UCST. Fast cooling freezes the surfacemorphology into a metastable state with enough PE at the surface toadequately delay dispersion. Too much PE would make a barrel that willnot have adequate dispersibility. Enough plasticizer glycerin is addedto allow fast compounding and high speed injection molding. The presentdisclosure makes a metastable polymer into a stable polymeric structuredproduct, or at least stable for a period long enough for the tamponapplicator to be used.

Additional information with respect to the morphology of the presentdisclosure and the potential for stabilization by specific interactionsbetween components can be found with respect to hydrophobic interactionsbetween the PVOH and PE atwww.google.com/?gws_rd=ssl#q=Ultra-thin+films+on+polyvinyl+alcohol+on+hydrophobic+surfaces,and with respect to hydrophilic/hydrogen bonding interactions betweenPVOH, PEG, and glycerin atwww.meplab.fudan.edu.cn/infonet/assays/1999/27.pdf, both of which areincorporated herein by reference to the extent they do not conflictherewith. Further information can be found atwww.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwi-utWwlurPAhUq0oMKHTKaD5QQFggcMAA&url=https%3A%2F%2Fwww.physics.ncsu.edu%2Fstxm%2Fpubs%2FMacroMatEng00_274-1.pdf&usg=AFQjCNHrrc_Fput_ZYDRKbmTaR8ttMZrwQ&bvm=bv.136499718,d.amc,and in Kolahchi et al., “Surface morphology and properties of ternarypolymer blends: effect of the migration of minor components,” J. Phys.Chem. B 2014, 118, 6316-6323, both of which are incorporated herein byreference to the extent they do not conflict herewith.

I. APPLICATOR DESIGN

As illustrated in the tampon assembly 10 of FIG. 1, the tamponapplicator 54 comprises an outer tube 40 and an inner tube 42. The outertube 40 is sized and shaped to house a tampon 52. A portion of the outertube 40 is partially broken away in FIG. 1 to illustrate the tampon 52.In the illustrated aspect, the outer tube 40 has a substantially smoothexterior surface, which facilitates insertion of the tampon applicator54 without subjecting the internal tissues to abrasion. The outer tube40 may be coated to give it a high slip characteristic. The illustratedouter tube 40 is a straight, elongated cylindrical tube. It isunderstood however that the applicator 54 could have different shapesand sizes than those illustrated and described herein.

Extending outwardly from the outer tube is an insertion tip 44. Theinsertion tip 44, which is formed as one-piece with the outer tube 40,may be dome-shaped to facilitate insertion of the outer tube into awoman's vagina in a comfortable manner. The illustrated insertion tip 44is made of a thin, flexible material and has a plurality of soft,flexible petals 46 that are arranged to form the dome-shape. The petals46 are capable of radially flexing (i.e., bending outward) to provide anenlarged opening through which the tampon 52 can exit when it is pushedforward by the inner tube 42. It is to be understood, however, that theouter tube 40 may be formed without the insertion tip 44. Without theinsertion tip, the outer tube includes an opened end (not shown) throughwhich the tampon 52 can exit when it is pushed forward by the innertube.

The inner tube 42 is an elongate cylinder that is used to engage thetampon 52 contained in the outer tube 40. A free end 48 of the innertube 42 is configured so that the user can move the inner tube withrespect to the outer tube 40. In other words, the free end 48 functionsas a grip for the forefinger of the user. The inner tube 42 is used topush the tampon 52 out of the outer tube 40 and into the woman's vaginaby telescopically moving into the outer tube. As the inner tube 42 ispushed into the outer tube 40 by the user, the tampon 52 is forcedforward against the insertion tip 44. The contact by the tampon 52causes the petals 46 of the insertion tip 44 to radially open to adiameter sufficient to allow the tampon to exit the outer tube 40 andinto the woman's vagina. With the tampon 52 properly positioned in thewoman's vagina, the tampon applicator 54 is withdrawn. In a usedconfiguration of the tampon applicator 54, the inner tube 42 is receivedin the outer tube 40.

The inner tube 42, the outer tube 40, and the insertion tip 44 can beformed from one or more layers, where one layer includes thewater-dispersible, thermoplastic composition of the present invention.Further, to prevent the applicator 54 from prematurely disintegratingdue to moisture during use and/or to reduce the coefficient of frictionof the applicator 54 to make it more comfortable for the user, it can becoated with a water-insoluble material that also has a low coefficientof friction to enhance comfort and prevent disintegration duringinsertion of the applicator 54. The structure of the tampon applicatordescribed above is conventional and known to those skilled in the art,and is described, for instance, in U.S. Pat. No. 8,317,765 to Loyd, etal., which is incorporated herein in its entirety by reference theretofor all purposes. Other tampon applicator structures that can be formedfrom the thermoplastic composition of the present invention aredescribed, for instance, in U.S. Pat. No. 4,921,474 to Suzuki, et al.and U.S. Pat. No. 5,389,068 to Keck, as well as U.S. Patent ApplicationPublication Nos. 2010/0016780 to VanDenBogart, et al. and 2012/0204410to Matalish, et al., which are incorporated herein in their entirety byreference thereto for all purposes.

Generally speaking, frictional forces occur between any two contactingbodies where there are forces tending to slide one of the bodiesrelative to the other. The frictional forces act parallel to thecontacting surfaces and opposite the forces tending to cause slidingbetween the bodies. Further, the frictional forces are proportional tonormal forces on the bodies and to the tendency of the bodies to gripeach other.

As used herein, the coefficient of friction is the ratio of thefrictional force between the bodies to the normal force between thebodies. The coefficient of friction is different between bodies at restand bodies moving relative to each other. In general, two bodiescontacting one another, but not moving relative to one another, willexhibit greater frictional resistance to motion than bodies that aremoving relative to one another. Hence, a static coefficient of friction(i.e., a coefficient of friction between bodies that are not movingrelative to each other) can but need not necessarily be somewhat greaterthan a dynamic coefficient of friction (i.e., a coefficient of frictionbetween bodies that are moving relative to each other). Largercoefficients of friction correspond to larger amounts of frictionbetween bodies, while smaller frictional coefficients correspond tosmaller amounts of friction. As used further herein, the termcoefficient of friction refers to at least one of a static coefficientfriction and a dynamic coefficient of friction. In particularly suitableaspects, the coefficient of friction differential described previouslyis present for both static and dynamic coefficients of friction.

One or more additives can be added to the polymeric first layer 81 ofthe barrel 23 (prior to molding) to enhance the slip characteristic(e.g., to provide a low coefficient of friction) of the barrel outersurface at least at the central region 43 of the barrel and moresuitably at the central region and tip region 45 of the barrel. Forexample, suitable such additives include without limitation erucamide,dimethicone, oleamide, fatty acid amide and combinations thereof. It isunderstood that other additives can used to provide enhanced slipcharacteristics to the barrel 23 outer surface without departing fromthe scope of this disclosure. In other aspects the barrel 23 caninstead, or additionally, be coated with a friction reducing, or slipagent such as, without limitation, wax, polyethylene, silicone,cellophane, clay and combinations thereof. In still other suitableaspects the barrel 23 can include a polymer blend melted together andco-extruded to provide a low coefficient of friction.

In the illustrated aspect, the barrel 23 is further constructed so thatthe barrel outer surface at the tip region 45 has a lower coefficient offriction than at the central region 43 of the barrel to facilitateeasier insertion of the barrel, inner end first, into the vaginal canal.This is particularly useful on days that a period is relatively light.For example, the outer surface of the barrel 23 at the tip region 45 canbe configured to have a substantially lower surface roughness than atthe central region 43 of the barrel, and more suitably the tip regioncan be substantially smooth or polished to reduce the coefficient offriction of the tip region relative to that of the central region. As aparticular example, the surface roughness (that provides a tactileperception to the user) of the central region 43 of the barrel can havea surface roughness of less than or equal to about 36 and is moresuitably about 27 in accordance with VDI Richtlinie [Standard] 3400. VDIRichtlinie 3400 has the German title: “Electroerosive Bearbeitung,Begriffe, Verfahren, Anwendung” [Electrical Discharge Machining,Definitions, Process, Application], published by the Verein DeutscherIngenieure [Association of German Engineers] in June 1975.

In other aspects, the tip region 45 of the barrel 23 can instead, oradditionally be coated with a friction reducing agent so that the outersurface of the barrel at the tip region has a lower coefficient offriction than that of the central region of the barrel. Providing asurface roughness differential between the tip region 45 and the centralregion 43 also serves as a visual indicator of the reduced frictioncoefficient at the tip region.

II. APPLICATOR MATERIALS

As described above, a water-dispersible injection-moldable resin for usein a flushable tampon applicator of the structure described herein isneeded. All previous attempts to make a flushable injection moldedtampon applicator have failed because the material could not beinjection molded at low cycle times, and because the applicators weredifficult to insert under moist conditions or had poor shelf-lives underhigh-moisture conditions. This disclosure allows for the successfulproduction of a flushable tampon applicator that provides consumers aclean experience by eliminating the messiness of applicator disposal.

PVOH is a water-soluble, repulpable, and biodegradable resin withexcellent aroma and oxygen barrier properties and resistance to mostorganic solvents. The polymer is used extensively in adhesives, textilesizing, and paper coating. Despite its excellent mechanical, physical,and chemical properties, the end uses of PVOH have been limited to thoseuses in which it is supplied as a solution in water. This limitation ispartly due to the fact that vinyl alcohol polymers in an unplasticizedstate have a high degree of crystallinity and show little to nothermoplasticity before the occurrence of decomposition that starts atabout 170° C. and becomes pronounced at 200° C., which is well below itscrystalline melting point.

Attempts have been made to use PVOH in injecting molding for disposablesanitary products such as tampon applicators. These can yield moldedparts that are stiff when removed from the molding machine but pick upmoisture from the atmosphere and become too flexible for machinehandling in the manufacture of tampon applicators. Other attempts usecomplex mixtures of materials, multiple types of PVOH, and/or variouscoatings. Tampon applicators made primarily from PVOH arewater-dispersible and biodegradable; however, such applicators have beenshown to suffer from issues involving moisture sensitivity, stability,odor, and stickiness. Hence there have been no commercially successfullaunches of these applicators.

Other attempts in addressing the flushability of plastic tamponapplicators include plastic applicators made from other water-solublematerials such as polyethylene oxide polymers, thermoplastic starch, andhydroxypropyl cellulose; plastic tampon applicators made fromcombinations of water-soluble and water-insoluble/biodegradablematerials such as combinations of PVOH and polycaprolactone,combinations of polyethylene oxide and polycaprolactone, combinations ofpolyethylene oxide and polyolefins such as polypropylene andpolyethylene; and combinations of PVOH and polyethylene oxide polymers.Again, none of these attempts to produce a truly flushable product haveseen commercial application.

A water-dispersible injection-moldable resin based on PVOH has beendeveloped for use as the primary resin for injection molding outer andinner (plunger) tubes in current tampon applicators. The resin is ablend of single low molecular weight partially-hydrolyzed PVOH, aplasticizer such as glycerin, a high molecular weight polyethyleneglycol (PEG), and a hydrophobic polymer component such as polyethylene.In addition, the applicator resin formulation can include othermaterials such as color additives, antioxidants, surface finish, andrelease agents/lubricants such as a euricamide release agent.

A single grade of PVOH, specifically a PVOH partially hydrolyzed at87-89%, with a low molecular weight provides the speed of dispersibilityrequired for flushability. This PVOH is plasticized with glycerin toadjust the melt flow rate to be compatible with injection molding. Thelevel of plasticizer is low enough that it does not bloom duringstorage, which would result in an unusable product. The plasticizerlevel also contributes to the softness or hardness of the final product.A high molecular weight polyethylene glycol is added to reduce wetcoefficient of friction.

A. Polyvinyl Alcohol Polymer

The water-dispersible, thermoplastic composition includes one or morepolymers containing a repeating unit having a functional hydroxyl group,such as polyvinyl alcohol (“PVOH”) and copolymers of polyvinyl alcohol(e.g., ethylene vinyl alcohol copolymers, methyl methacrylate vinylalcohol copolymers, etc.). Vinyl alcohol polymers, for instance, have atleast two or more vinyl alcohol units in the molecule and can be ahomopolymer of vinyl alcohol or a copolymer containing other monomerunits. Vinyl alcohol homopolymers can be obtained by hydrolysis of avinyl ester polymer, such as vinyl formate, vinyl acetate, or vinylpropionate. Vinyl alcohol copolymers can be obtained by hydrolysis of acopolymer of a vinyl ester with an olefin having 2 to 30 carbon atoms,such as ethylene, propylene, or 1-butene; an unsaturated carboxylic acidhaving 3 to 30 carbon atoms, such as acrylic acid, methacrylic acid,crotonic acid, maleic acid, or fumaric acid or an ester, salt, anhydrideor amide thereof; an unsaturated nitrile having 3 to 30 carbon atoms,such as acrylonitrile or methacrylonitrile; a vinyl ether having 3 to 30carbon atoms, such as methyl vinyl ether or ethyl vinyl ether; and soforth. The degree of hydrolysis can be selected to optimize solubility,for example, of the polymer. For example, the degree of hydrolysis canbe from about 60 mole % to about 95 mole %, in some aspects from about80 mole % to about 90 mole %, in some aspects from about 85 mole % toabout 89 mole %, and in some aspects from about 87 mole % to about 89mole %. These partially-hydrolyzed polyvinyl alcohols are cold-watersoluble. In contrast, completely-hydrolyzed or nearly-hydrolyzedpolyvinyl alcohols are not soluble in cold water.

Examples of suitable partially-hydrolyzed polyvinyl alcohol polymers areavailable under the designations SELVOL 203, 205, 502, 504, 508, 513,518, 523, 530, or 540 PVOH from Sekisui Specialty Chemicals America, LLCof Dallas, Tex. For instance, SELVOL 203 PVOH has a percent hydrolysisof 87% to 89% and a viscosity of 3.5 to 4.5 centipoise (cps) asdetermined from a 4% solids aqueous solution at 20° C. SELVOL 205 PVOHhas a percent hydrolysis of 87% to 89% and a viscosity of 5.2 to 6.2 cpsas determined using a 4% solids aqueous solution at 20° C. SELVOL 502PVOH has a percent hydrolysis of 87% to 89% and a viscosity of 3.0 to3.7 cps as determined using a 4% solids aqueous solution at 20° C.SELVOL 504 PVOH has a percent hydrolysis of 87% to 89% and a viscosityof 4.0 to 5.0 cps as determined from a 4% solids aqueous solution at 20°C. SELVOL 508 PVOH has a percent hydrolysis of 87% to 89% and aviscosity of 7.0 to 10.0 cps as determined as determined from a 4%solids aqueous solution at 20° C. Other suitable partially-hydrolyzedpolyvinyl alcohol polymers are available under the designations ELVANOL50-14, 50-26, 50-42, 51-03, 51-04, 51-05, 51-08, and 52-22 PVOH fromDuPont. For instance, ELVANOL 51-05 PVOH has a percent hydrolysis of 87%to 89% and a viscosity of 5.0 to 6.0 cps as determined from a 4% solidsaqueous solution at 20° C.

In the present disclosure, the polyvinyl alcohols characterized ashaving a low viscosity include SELVOL 502 PVOH (3.0 to 3.7 cps), wherethe midpoint or average viscosity for low-viscosity polyvinyl alcohol isgenerally less than about 3.35 cps, as determined by averaging theminimum and maximum viscosities provided for commercially availablepartially-hydrolyzed polyvinyl alcohols. The polyvinyl alcoholscharacterized as having a high viscosity include SELVOL 203 PVOH (3.5 to4.5 cps), SELVOL 504 PVOH (4.0-5.0 cps), ELVANOL 51-05 PVOH (5.0 to 6.0cps), SELVOL 205 PVOH (5.2 to 6.2 cps), and SELVOL 508 PVOH (7.0-10.0cps), where the midpoint or average viscosity for the high-viscositypolyvinyl alcohol polymers is at least about 4.0 cps, as determined byaveraging the minimum and maximum viscosities provided forcommercially-available partially-hydrolyzed polyvinyl alcohols.

B. Polyethylene Glycol

Polyethylene glycol (PEG) having average molecular weights of betweenabout 300 and 2,000,000, alternatively, between about 500 and 2,000,000,alternatively between about 1000 and 1,000,000, alternatively betweenabout 1000 and 400,000, alternatively, between about 1000 and 100,000,alternatively between about 3000 and 100,000 are desirable for use inthe present disclosure. In another aspect, PEGs having average molecularweights between about 3000 and 35,000 are desirable. As the ethyleneoxide chain impacts functionality of the invention, PEG variants withdifferent functional groups on each end will also be acceptable for usein the invention. Linear as well as branched forms will likewise beacceptable for use in the invention. In a further aspect, PEGs havingaverage molecular weights of between about 4000 and 12000 are desirable.In another aspect, PEGs having average molecular weights of about 8000are desirable. Such PEG materials are available, for example, from theDow Chemical Company under the trade name CARBOWAX.

C. Plasticizer

A plasticizer is also employed in the water-dispersible thermoplasticcomposition to help render the water-soluble polymer thermoplastic andthus suitable for extrusion into pellets and subsequent injectionmolding. Suitable plasticizers include, for instance, polyhydric alcoholplasticizers such as sugars (e.g., glucose, sucrose, fructose,raffinose, maltodextrose, galactose, xylose, maltose, lactose, mannose,and erythrose), sugar alcohols (e.g., erythritol, xylitol, malitol,mannitol, and sorbitol), polyols (e.g., ethylene glycol, glycerol,propylene glycol, dipropylene glycol, butylene glycol, and hexanetriol), and polyethylene glycols. Also suitable arehydrogen-bond-forming organic compounds that do not have a hydroxylgroup, including urea and urea derivatives; anhydrides of sugar alcoholssuch as sorbitan; animal proteins such as gelatin; vegetable proteinssuch as sunflower protein, soybean proteins, cotton seed proteins; andmixtures thereof. Other suitable plasticizers can include phthalateesters, dimethyl and diethylsuccinate and related esters, glyceroltriacetate, glycerol mono and diacetates, glycerol mono, di, andtripropionates, butanoates, stearates, lactic acid esters, citric acidesters, adipic acid esters, stearic acid esters, oleic acid esters, andother acid esters. Aliphatic acids can also be used, such as ethyleneacrylic acid, ethylene maleic acid, butadiene acrylic acid, butadienemaleic acid, propylene acrylic acid, propylene maleic acid, and otherhydrocarbon-based acids. A low molecular weight plasticizer ispreferred, such as less than about 20,000 g/mol, preferably less thanabout 5,000 g/mol, and more preferably less than about 1,000 g/mol.

The plasticizer can be incorporated into the composition of the presentdisclosure using any of a variety of known techniques. For example,water-soluble polymers can be “pre-plasticized” prior to incorporationinto the composition. Alternatively, one or more of the components canbe plasticized at the same time they are blended together. Batch and/orcontinuous melt blending techniques can be employed to blend thecomponents. For example, a mixer/kneader, Banbury mixer, Farrelcontinuous mixer, single-screw extruder, twin-screw extruder, roll mill,etc. can be used. One particularly suitable melt-blending device is aco-rotating, twin-screw extruder (e.g., USALAB twin-screw extruderavailable from Thermo Electron Corporation of Stone, England or anextruder available from Werner-Pfleiderer from Ramsey, N.J.). Suchextruders can include feeding and venting ports and provide highintensity distributive and dispersive mixing. For example, thewater-soluble polymer can be initially fed to a feeding port of thetwin-screw extruder to form a composition. Thereafter, a plasticizer canbe injected into the composition. Alternatively, the composition can besimultaneously fed to the feed throat of the extruder or separately at adifferent point along the length of the extruder. Melt blending canoccur at any of a variety of temperatures, such as from about 30° C. toabout 240° C., in some aspects, from about 40° C. to about 200° C., andin other aspects, from about 50° C. to about 180° C.

Plasticizers can be present in the water-dispersible, thermoplasticcomposition in an amount ranging from about 2 wt. % to about 50 wt. %,such as from about 3 wt. % to about 45 wt. %, and such as from about 5wt. % to about 40 wt. %, based on the total weight of the composition.In some aspects, the plasticizer can be present in an amount of 10 wt. %or greater, such as from about 10 wt. % to about 35 wt. %, such as fromabout 10 wt. % to about 30 wt. %, and such as from about 10 wt. % toabout 25 wt. % based on the total weight of the composition.

D. Hydrophobic Polymeric Component

It appears that a small amount of a hydrophobic polymer added to theblend enhances the performance of the tampon applicator. The hydrophobicpolymer can be added to the blend on its own, or as a component inanother addition, such as in a coloring agent. Hydrophobic polymersinclude polyethylene.

It is believed that during molding, when the temperature falls below theblend UCST, the hydrophobic polymer such as PE migrates to the surfacewith the PEG. During this migration the PE migrates initially earlierand faster than the PEG to the surface, but later the PEG begins todisplace the PE at the surface. The PEG does not begin to migrate untilthe blend temperature is below the UCST. Fast cooling freezes thesurface morphology into a metastable state with enough PE at the surfaceto adequately delay dispersion. Too much PE, however, would make atampon applicator barrel that will not have adequate dispersibility.

E. Coloring Agents

In addition, the water-dispersible, thermoplastic composition cancontain one or more coloring agents (e.g., pigment or dye). Typically, apigment refers to a colorant based on inorganic or organic particlesthat do not dissolve in water or solvents. Usually pigments form anemulsion or a suspension in water. On the other hand, a dye generallyrefers to a colorant that is soluble in water or solvents.

The pigment or dye can be present in an amount effective to be visibleonce the composition is formed into an injection molded article so thatarticles formed from the composition can have an aesthetically-pleasingappearance to the user. Suitable organic pigments include dairylideyellow AAOT (for example, Pigment Yellow 14 CI No. 21 095), dairylideyellow AAOA (for example, Pigment Yellow 12 CI No. 21090), Hansa Yellow,CI Pigment Yellow 74, Phthalocyanine Blue (for example, Pigment Blue15), lithol red (for example, Pigment Red 52:1 CI No. 15860:1),toluidine red (for example, Pigment Red 22 CI No. 12315), dioxazineviolet (for example, Pigment Violet 23 CI No, 51319), phthalocyaninegreen (for example, Pigment Green 7 CI No. 74260), phthalocyanine blue(for example, Pigment Blue 15 CI No. 74160), and naphthoic acid red (forexample, Pigment Red 48:2 CI No. 15865:2). Inorganic pigments includetitanium dioxide (for example, Pigment White 6 CI No. 77891), ironoxides (for example, red, yellow, and brown), chromium oxide (forexample, green), and ferric ammonium ferrocyanide (for example, blue).

Suitable dyes that can be used include, for instance, acid dyes andsulfonated dyes including direct dyes. Other suitable dyes include azodyes (e.g., Solvent Yellow 14, Dispersed Yellow 23, and Metanil Yellow),anthraquinone dyes (e.g., Solvent Red 111, Dispersed Violet 1, SolventBlue 56, and Solvent Orange 3), xanthene dyes (e.g., Solvent Green 4,Acid Red 52, Basic Red 1, and Solvent Orange 63), azine dyes, and thelike.

When present, the coloring agents can be present in thewater-dispersible thermoplastic composition in an amount ranging fromabout 0.5 wt. % to about 20 wt. %, such as from about 1 wt. % to about15 wt. %, such as from about 1.5 wt. % to about 12.5 wt %, and such asfrom about 2 wt. % to about 10 wt. % based on the total weight of thewater-dispersible thermoplastic composition.

F. Other Optional Components

In addition to the components noted above, other additives can also beincorporated into the composition of the present disclosure, such asdispersion aids, melt stabilizers, processing stabilizers, heatstabilizers, light stabilizers, antioxidants, heat aging stabilizers,whitening agents, antiblocking agents, bonding agents, and lubricants.Dispersion aids, for instance, can also be employed to help create auniform dispersion of the PVOH/plasticizer mixture and retard or preventseparation into constituent phases. Likewise, the dispersion aids canalso improve the water dispersibility of the composition. Although anydispersion aid can generally be employed in the present disclosure,surfactants having a certain hydrophilic/lipophilic balance (“HLB”) canimprove the long-term stability of the composition. The HLB index iswell known in the art and is a scale that measures the balance betweenthe hydrophilic and lipophilic solution tendencies of a compound. TheHLB scale ranges from 1 to approximately 50, with the lower numbersrepresenting highly lipophilic tendencies and the higher numbersrepresenting highly hydrophilic tendencies. In some aspects of thepresent disclosure, the HLB value of the surfactants is from about 1 toabout 20, from about 1 to about 15, or from about 2 to about 10. Ifdesired, two or more surfactants can be employed that have HLB valueseither below or above the desired value, but together have an averageHLB value within the desired range.

One particularly suitable class of surfactants for use in the presentdisclosure is that of nonionic surfactants, which typically have ahydrophobic base (e.g., a long chain alkyl group or an alkylated arylgroup) and a hydrophilic chain (e.g., chain containing ethoxy and/orpropoxy moieties). For instance, some suitable nonionic surfactants thatcan be used include, but are not limited to, ethoxylated alkylphenols,ethoxylated and propoxylated fatty alcohols, polyethylene glycol ethersof methyl glucose, polyethylene glycol ethers of sorbitol, ethyleneoxide-propylene oxide block copolymers, ethoxylated esters of fatty(C.sub.8-C.sub.18) acids, condensation products of ethylene oxide withlong chain amines or amides, condensation products of ethylene oxidewith alcohols, fatty acid esters, monoglyceride or diglycerides of longchain alcohols, and mixtures thereof. In one particular aspect, thenonionic surfactant can be a fatty acid ester, such as a sucrose fattyacid ester, glycerol fatty acid ester, propylene glycol fatty acidester, sorbitan fatty acid ester, pentaerythritol fatty acid ester,sorbitol fatty acid ester, and so forth. The fatty acid used to formsuch esters can be saturated or unsaturated, substituted orunsubstituted, and can contain from 6 to 22 carbon atoms, from 8 to 18carbon atoms, or from 12 to 14 carbon atoms. In one particular aspect,mono- and di-glycerides of fatty acids can be employed in the presentdisclosure.

When employed, the dispersion aid(s) typically constitute from about0.01 wt. % to about 15 wt. %, from about 0.1 wt. % to about 10 wt. %,from about 0.5 wt. % to about 5 wt. %, and from about 1 wt. % to about 3wt. % based on the total weight of the water-dispersible thermoplasticcomposition.

III. APPLICATOR STABILITY/WRAPPER

Flushable articles need to be protected from moisture because an articlethat will disperse in water is prone to degradation in humidity or othermoisture. An article wrapper material with a WVTR rating of at most 0.05g/100 in²/day is generally required.

IV. OPTIMIZING CONDITIONS

The base resin of choice for a flushable applicator is Selvol 502, apartially-hydrolyzed PVOH with a viscosity range of 3.0-3.7 cps and35-40% crystalline and an average molecular weight of 20,000 daltons.Glycerin plasticizes the PVOH and softens the resultant applicator tubeswith an optimum content around 11-13%, resulting in a melt flow of 90g/10 min for the compounded resin. The addition of high molecular weightPEG (e.g., PEG 8000) reduces the wet insertion force of PVOH applicatorsto that of current polyethylene applicators.

This base resin provides a thermoformable PVOH composition that can bemelt extruded or injection molded into a thin wall structure which isflushable and biodegradable while retaining its wall integrity andstiffness at high humidity.

PEG may be uniformly dispersed in the PVOH; while in the solid state,the PEG molecules do not inhabit intact crystallites, and plasticizationoccurs in the amorphous region only, during crystallization, the PEGspecies are eliminated from the PVOH lattice. The PEG species in thePVOH matrix may form hydrogen bonds with the PVOH segments. Whencrystallization occurs, such PEG species should be removed from the PVOHcrystallites, as a result, the crystallization would be delayed. Themore the PEG species that are incorporated, the slower would be thecrystallization.

In one aspect, a specific formulation meets physical properties and userneeds such as insertion and removal force and pledget expulsion force.This formulation includes a blend of 55 wt. % to 75 wt. % lowermolecular weight partially-hydrolyzed PVOH, 15 wt. % to 25 wt. % highermolecular weight PEG, 9 wt. % to 14 wt. % glycerin, 3 wt. % to 4 wt. %colorant within an ethylene matrix, <1 wt. % colorant package additivesincluding one or more of the following processing, stabilization, andfinishing adjuncts: antioxidants, finishing additive, release agents,and processing lubricants

The low molecular weight PVOH is highly dispersible, breaking down in amodified slosh box test in 30-40 minutes. Its melt flow rate is easilymodified to allow for injection molding with only small amounts ofplasticizer (9 wt. % to 13 wt. %) that eliminates the greasy feelassociated with surface migration of glycerin when incorporated at thehigher levels used for higher molecular weight PVOH resins or mixturesof PVOH resins.

The processes described herein using PVOH/PEG/glycerin/PE work best inthe range of 40° C. to 200° C. The operation temperature of the extruderwill be between the liquid-liquid separation temperature of thePVOH/PEG/glycerin blend and the melting temperatures of PVOH & PEG inthe blend, and the decomposition temperature of the PVOH/PEG/glycerinblend. At a temperature above the liquid-liquid separation temperaturethe blend is miscible and below it the blend is immiscible. Theapproximate separation temperature will be between approximately 55° C.and 60° C. A literature value (US2003/0156618) for the PVOH/PEG UCST isaround 42° C. A literature value (SELVOL 205 PVOH trade literature) forthe glass transition temperature of “pure” PVOH is around 58° C.; thevalue found herein was between 50° C. and 75° C. A literature value(CARBOWAX PEG 8000 PEG, Dow technical data sheet) for the melting pointof PEG 8000 is between 55° C. and 62° C.; the value found herein wasaround 65° C. The blend value for the melting point of PEG found hereinis around 59° C. and the blend value for the glass transition of PVOHappears to be around 25° C. The literature value for the melting pointof pure glycerin is around 18° C. The approximate decompositiontemperature is between 170° C. and 200° C. The literature value forrapid thermal decomposition of glycerin indicates that pure glycerinbegins to decompose around 177° C. and ends around 231° C. Theliterature value for rapid thermal decomposition of PVOH is between 200°C. and 500° C.; the value found herein is over 200° C. The literaturevalue for the rapid thermal decomposition of PEG is over 300° C.; thevalue found herein is over 320° C.

It appears a certain amount of PE or any other hydrophobic andimmiscible polymer needs to be included in the PVOH/PEG/glycerin/PEblend. The composition described herein includes a small amount of ahydrophobic and immiscible polymer within the blend. The literature(U.S. Pat. No. 6,544,661) indicates that the amount of PE will need bebelow 20% to allow some dispersibility; the work described hereinsuggests a more preferred amount of less than 5%.

Described herein is the process of making PVOH compositions where thenecessary energy is added to melt the PVOH and additional energy isadded to shear the areas of PVOH crystallinity in the melt, while at thesame time removing the shearing energy to prevent the melt temperaturefrom exceeding the PVOH decomposition temperature. The extruder requiresintensive mixing elements to provide the requisite shearing energy. Theshearing energy generated in a particular zone of the extruder shouldnot be greater than that which can be removed by cooling, otherwisedecomposition results. The process provides sufficient mixing of thePVOH/PEG species and rapid cooling of the melt to reduce the finalcrystallinity and maintain the interaction of PVOH and PEG species. ThePEG acts as a spacer to enlarge the distance among PVOH segments. Thespacing effect decreases the glass transition temperature of PVOH andalong with the presence of glycerin, results in plasticization.

Injection moldable formulations of PVOH and PEG were developed throughcompounding on a Coperion ZSK30 co-rotating twin screw extruder. Theprocess involves first melting and mixing the PVOH and PEG, plasticizingthe PVOH with glycerin, de-volatizing of moisture from the melt,followed by rapidly cooling of the melt with air prior to pelletizationof the cooled strands.

The Coperion ZSK30 has seven heated zones over thirteen barrel sections.Resin pellets can be feed into the main feeding zone using any of thethree feeders. The melt process is initiated in the second barrelsection followed by the injection of the liquid plasticizer. The melt isintensively mixed prior to the addition of filler or additive, whenapplicable, in barrel seven. Further mixing is applied to the meltbefore moisture and volatiles are vented in barrel twelve. The melt ispressurized and extruded through a three-hole strand die. A typicaltemperature profile using a screw speed of 160 rpm is shown in Table 1.

TABLE 1 PVOH Compounding Temperature Profile HZ-1 HZ-2 HZ-3 HZ-4 HZ-5HZ-6 Die (° C.) (° C.) (° C.) (° C.) (° C.) (° C.) (° C.) 90 130 165 195190 180 160

The resulting strands were well mixed without evidence of gels orcrystals with a moisture content of 0.5-0.8%. The strands were cooledwith room temperature air (22° C.) air, using only 6 of a possible 13fans (500 fpm/fan) along the cooling belt, moving at 18′ per minute,prior to being pelletized. The resulting pellets have a diameter of 0.12inches and a height of 0.13 inches. The retention time for the PVOH inthe extruder was between 1.25 and 3.75 minutes.

Effect of temperature and screw speed was studied using threetemperature profiles and three screw speeds (160, 300, 500 rpm), asshown in Table 2.

TABLE 2 Compounding Optimization Temperature Profiles HZ-1 HZ-2 HZ-3HZ-4 HZ-5 HZ-6 Die (° C.) (° C.) (° C.) (° C.) (° C.) (° C.) (° C.)Ultra Low 90 130 130 130 130 130 150 Low Temp 90 140 150 150 150 150 150High Temp 90 130 165 195 190 180 160

The PVOH raw material as received from the vendor contains between 2-3%moisture. To consistently remove this moisture during compounding toless than 1%, the melt must be raised above 150° C. This remainingmoisture acts as a plasticizer and therefore raises the melt flow from60 g/10 min to 80 g/10 min.

The optimum conditions, where the specific energy required is lowest, isat the higher temperature and lowest screw speed. These optimumconditions also produce the best material physical properties.

Coefficient of friction and dispersibility were not affected by theconditions of compounding as was expected.

A method of compounding has been optimized for screw design, screwspeed, and temperature profile on a co-rotating twin screw extruder toproduce a compounded formulated resin that has removed the PVOHcrystallinity, completely dispersed the PVOH and PEG components, reducedmoisture, and removed heat from the PVOH during compounding to minimizedegradation. By quickly air cooling the polymer strands, the PVOH/PEGblend was maintained and re-crystallization of the PVOH domains was notallowed.

With respect to the specific situation of an injection-molded tamponapplicator, a user-friendly, successful flushable tampon applicator isaccomplished by the creation of a unique morphology within the plasticapplicator. Compounding has created a blend of PVOH and PEG in which thepolymer chains are equally dispersed with each other. Quick coolingfreezes this morphology in the outer thicknesses of the plastic part.Maintaining the mixture of PVOH and PEG allows the applicator to beinserted under moist conditions with the equivalent force of a standardpolyethylene applicator. This solves what has always been the drawbackof PVOH applicators and more specifically single grade PVOH applicators.

PVOH is typically considered to be an adhesive under wet conditions, andPEG can be used as an adhesion amplifier. The unexpected result ofcombining PVOH and PEG was the production of a material with reducedtackiness, even under wet conditions. Without being limited to bytheory, it appears that the PVOH and the PEG, both beingporous-structure-forming, become interspersed, each essentiallyoccupying the pores of the other. This interspersion pushes the smallamount of polyethylene available in the colorant package or added on itsown to the surface where it forms a very thin skin. This skin protectsthe water-dispersible components of the formulation from moisture longenough to prevent the water-dispersible components from becoming tacky,thus reducing the wet insertion force of the applicator.

Reference now will be made in detail to various aspects of thedisclosure, one or more examples of which are set forth below. Eachexample is provided by way of explanation of the disclosure, notlimitation of the disclosure. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present disclosure without departing from the scope or spirit ofthe disclosure. For instance, features illustrated or described as partof one aspect, can be used on another aspect to yield a still furtheraspect. Thus, it is intended that the present disclosure covers suchmodifications and variations as come within the scope of the appendedclaims and their equivalents.

V. EXAMPLES

A. Test Methods

Melt Flow Rate: The melt flow rate (“MFR”) is the weight of a polymer(in grams) forced through an extrusion rheometer orifice (0.0825-inchdiameter) when subjected to a load of 2160 grams in 10 minutes,typically at 190° C. or 230°. Unless otherwise indicated, melt flow rateis measured in accordance with ASTM Test Method D1239 with a TiniusOlsen Extrusion Plastometer. It should be noted that the melt flow ratemeasured at 190° C. can be referred to as the melt flow index (MFI),while those measured at other temperatures are called melt flow rates(MFR).

Tensile Properties: Tensile properties were determined by following ASTMD638-10 guidelines. ASTM D638-10 Type V injection-molded test specimenswere pulled via a MTS Mold 810 tensile frame with a 3,300 pound loadcell. Five specimens were pulled from each example. The average valuesfor peak stress (tensile strength), elongation at break, and moduluswere reported. The maximum elongation that could be determined was 127%based on the tensile frame used, and the elongation was actually higherin the samples having 127% elongation readings.

Flushability Assessment: Disintegration testing was performed asoutlined in Guidance Document for Assessing the Flushability of NonwovenConsumer Products (INDA and EDANA, 2006); Test FG 522.2 Tier 2—Slosh BoxDisintegration Test. A round disc of each test resin is weighed andplaced in 2L of water maintained at 15° C. and agitated at 25-26 cyclesper minute. The time for the material to disperse completely and passthrough a 1 mm screen is recorded. After a maximum of 180 minutes, thetest is stopped, any remaining pieces larger than 1 mm are collected,dried, and weighed. The percent weight remaining of the disc isrecorded.

B. Materials

1. 65.5% lower molecular weight partially-hydrolyzed polyvinyl alcohol(SELVOL 502 PVOH produced by Sekisui, Dallas, Tex.)2. 20% higher molecular weight polyethylene glycol (CARBOWAX PEG 8000produced by Dow Chemical, Houston, Tex.)3. 11% glycerin (EMERY COGNIS 916 from Cognis Corporation, Cincinnati,Ohio)4. 3.5% colorant within an ethylene matrix (SCC 85283 from StandridgeColor Corp., Social Circle, Ga.)5. any one or more of the following processing, stabilization, andfinishing adjuncts: antioxidants, finishing additive, release agents,and processing lubricants (these are all part of the colorant package,<1%).

C. Process

Resin Compounding: In general, formulated resins were produced using aCoperion ZSK30 (30 mm diameter/1340 mm processing length compoundingscrew) co-rotating twin screw extruder with 7 heated sections and aresin-compounding screw design. Resins were produced at a rate of 20pounds per hour. PVOH and PVOH blends were dry blended prior to feedingthrough the main feed section. The color/slip agent was fed using aseparate feeder, also into the main feed section. Glycerin was injectedin section 3 and calcium carbonate was fed into section 4. Thetemperature profile per section, beginning at the main feed section was90°, 130°, 160°, 190°, 190°, 180°, and 145° C. The melt pressure rangedbetween 30-50 psi with the extruder torque of between 35 to 45%. Theextruded polymer was uniform in color and flowed well from the die. Thestrands were air cooled and pelletized.

Injection Molding: The examples where processed on a Boy Machine 22DInjection Molder. This model has a 24.2 ton clamping force unit, a 24 mmplasticizing unit, and a shot size of 34 grams. FIG. 2 is a schematic ofa basic injection molding machine 100. It shows the main components: theinjection unit 120, the clamping unit 140, and the control panel 160.The injection molding cycle begins when the mold 150 closes, pairing themoveable platen 152 with the fixed platen 154. At this point, the screw122 moves forward and injects the material through the nozzle 124 intothe sprue, and the material fills the mold 150 (runners, gates, andcavities). During the packing phase, additional material is packed intothe cavities. The material is cooled and solidifies in the mold whilethe screw 122 rotates counterclockwise backward, melting the plastic forthe next shot using heating bands 126. New material is supplied by thehopper 128. The mold 150 opens and the parts are ejected. The next cyclebegins when the mold 150 closes again.

The mold 200 used to produce specimens was an ASTM D638 standard testspecimen mold from Master Precision Products, Inc., as illustrated inFIG. 3. This mold 200 contains a Tensile Type I specimen 205, a rounddisk 210, a Tensile Type V specimen 215, and an Izod bar 220.

Injection-molded applicators were produced at Schoettli Group IndustieGrossholz, 8253 Diessenhofen, Switzerland using a pilot mold for bothbarrels and plungers.

A process to blend the above composition with a co-rotating twin screwextruder includes the steps:

1. Add solid components (PVOH, PEG, colorant) at a mass rate (lbs/hr)different for each solid (feed rate based as percentage of total output)2. Add liquid components at a mass rate lbs/hr (based as percentage oftotal output)3. Mix solids and liquids at an extruder speed of 160 rpm4. Melt solid components at an extruder temperature between 170° C. and195° C.5. Extrude strands of blend at melt temperature between 175° C. and 180°C.6. Quench strands with room temperature air (22° C.) air, using 6 of apossible 13 fans (500 fpm/fan) along the cooling belt, moving at 18 feetper minute7. Pelletize strands into pellets with a diameter of 0.12 inches and aheight of 0.13 inches8. Resonate time of the compounding process is between 1.25 and 3.75minutes and the energy input rate of the compounding process is between0.04 and 0.05 J/lb.

An injection molding process for the blend described above includes thesteps:

1. Pump a blend with a temperature between 175° C. and 180° C. intoparts mold with a surface temperature less than 10° C.2. The mold has a blend-compatible permanent release coating (tungstendisulfide)3. Keep in mold until blend solidify or vitrify or for a time betweent1-t2 (seconds)4. Eject the part from mold and cool the part with cool dry air.

D. Results

Both polyethylene (control applicators) and PVOH/PEG tubes from thistrial were tested for insertion force. PVOH/PEG tubes had lowerinsertion force than PVOH alone. The PVOH/PEG applicators wereequivalent to control applicators.

In a first particular aspect, a water-dispersible injection-moldablecomposition includes partially-hydrolyzed polyvinyl alcohol (PVOH),polyethylene glycol (PEG), plasticizer, and a hydrophobic polymericcomponent, wherein the composition has a melt flow index of 5-180.

A second particular aspect includes the first particular aspect, whereinthe hydrophobic polymeric component is a colorant within an ethylenematrix.

A third particular aspect includes the first and/or second aspect,wherein the hydrophobic polymeric component is polyethylene.

A fourth particular aspect includes one or more of aspects 1-3, whereinthe composition has a melt flow index of 60-90.

A fifth particular aspect includes one or more of aspects 1-4, whereinthe composition includes 55 wt. % to 75 wt. % partially-hydrolyzed PVOH.

A sixth particular aspect includes one or more of aspects 1-5, whereinthe composition includes 15 wt. % to 25 wt. % PEG.

A seventh particular aspect includes one or more of aspects 1-6, whereinthe composition includes 9 wt. % to 14 wt. % plasticizer.

An eighth particular aspect includes one or more of aspects 1-7, whereinthe plasticizer is glycerin.

A ninth particular aspect includes one or more of aspects 1-8, whereinthe PVOH has a viscosity range of 3.0-3.7 cps.

A tenth particular aspect includes one or more of aspects 1-9, whereinthe PVOH has a hydrolysis of 87% to 89%.

An eleventh particular aspect includes one or more of aspects 1-10,wherein the composition is flushable according to Guidance Document forAssessing the Flushability of Nonwoven Consumer Products (INDA andEDANA, 2006); Test FG 522.2 Tier 2—Slosh Box Disintegration Test.

In a twelfth particular aspect, a water-dispersible injection-moldablecomposition includes 55 wt. % to 75 wt. % partially-hydrolyzed polyvinylalcohol (PVOH), 15 wt. % to 25 wt. % polyethylene glycol (PEG), 9 wt. %to 14 wt. % plasticizer, and 3 wt. % to 4 wt. % hydrophobic polymericcomponent.

A thirteenth particular aspect includes the twelfth particular aspect,wherein the composition has a melt flow index of 5-180.

A fourteenth particular aspect includes the twelfth aspect and/or thethirteenth aspect, wherein the composition has a melt flow index of60-90.

A fifteenth particular aspect includes one or more of aspects 12-14,wherein the hydrophobic polymeric component is a colorant within anethylene matrix.

A sixteenth particular aspect includes one or more of aspects 12-15,wherein the hydrophobic polymeric component is polyethylene.

A seventeenth particular aspect includes one or more of aspects 12-16,wherein the PVOH has a hydrolysis of 87% to 89%.

In an eighteenth particular aspect, a water-dispersibleinjection-moldable composition includes 55 wt. % to 75 wt. %partially-hydrolyzed polyvinyl alcohol (PVOH), 15 wt. % to 25 wt. %polyethylene glycol (PEG), 9 wt. % to 14 wt. % glycerin, and 0.5 wt. %to 4 wt. % polyethylene.

A nineteenth particular aspect includes the eighteenth particularaspect, wherein the PVOH has a hydrolysis of 87% to 89%.

When introducing elements of the present disclosure or the preferredaspects(s) thereof, the articles “a,” “an,” “the,” and “said” areintended to mean that there are one or more of the elements. The terms“comprising,” “including,” and “having” are intended to be inclusive andmean that there can be additional elements other than the listedelements.

As various changes could be made in the above products without departingfrom the scope of the disclosure, it is intended that all mattercontained in the above description and shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

While the disclosure has been described in detail with respect to thespecific aspects thereof, it will be appreciated that those skilled inthe art, upon attaining an understanding of the foregoing, can readilyconceive of alterations to, variations of, and equivalents to theseaspects. Accordingly, the scope of the present disclosure should beassessed as that of the appended claims and any equivalents thereto.

What is claimed is:
 1. A water-dispersible injection-moldablecomposition comprising: partially-hydrolyzed polyvinyl alcohol (PVOH);polyethylene glycol (PEG); plasticizer; and a hydrophobic polymericcomponent, wherein the composition has a melt flow index of 5-180. 2.The composition of claim 1, wherein the hydrophobic polymeric componentis a colorant within an ethylene matrix.
 3. The composition of claim 1,wherein the hydrophobic polymeric component is polyethylene.
 4. Thecomposition of claim 1, wherein the composition has a melt flow index of60-90.
 5. The composition of claim 1, wherein the composition includes55 wt. % to 75 wt. % partially-hydrolyzed PVOH.
 6. The composition ofclaim 1, wherein the composition includes 15 wt. % to 25 wt. % PEG. 7.The composition of claim 1, wherein the composition includes 9 wt. % to14 wt. % plasticizer.
 8. The composition of claim 1, wherein theplasticizer is glycerin.
 9. The composition of claim 1, wherein the PVOHhas a viscosity range of 3.0-3.7 cps.
 10. The composition of claim 1,wherein the PVOH has a hydrolysis of 87% to 89%.
 11. The composition ofclaim 1, wherein the composition is flushable according to GuidanceDocument for Assessing the Flushability of Nonwoven Consumer Products(INDA and EDANA, 2006); Test FG 522.2 Tier 2—Slosh Box DisintegrationTest.
 12. A water-dispersible injection-moldable composition comprising:55 wt. % to 75 wt. % partially-hydrolyzed polyvinyl alcohol (PVOH); 15wt. % to 25 wt. % polyethylene glycol (PEG); 9 wt. % to 14 wt. %plasticizer; and 3 wt. % to 4 wt. % hydrophobic polymeric component. 13.The composition of claim 12, wherein the composition has a melt flowindex of 5-180.
 14. The composition of claim 12, wherein the compositionhas a melt flow index of 60-90.
 15. The composition of claim 12, whereinthe hydrophobic polymeric component is a colorant within an ethylenematrix.
 16. The composition of claim 12, wherein the hydrophobicpolymeric component is polyethylene.
 17. The composition of claim 12,wherein the PVOH has a hydrolysis of 87% to 89%.
 18. A water-dispersibleinjection-moldable composition comprising: 55 wt. % to 75 wt. %partially-hydrolyzed polyvinyl alcohol (PVOH); 15 wt. % to 25 wt. %polyethylene glycol (PEG); 9 wt. % to 14 wt. % glycerin; and 0.5 wt. %to 4 wt. % polyethylene.
 19. The composition of claim 18, wherein thePVOH has a hydrolysis of 87% to 89%.